The present invention relates to a tilt detecting device and a rotary laser apparatus which is capable of detecting a tilt based on a pattern.
As a tilt detecting means for use in a tilt detecting device, an encoder such as a linear encoder or a circle encoder or the like is extensively used.
However, in order to make a tilt detection accuracy more accurate, a size of the encoder must be increased. Further, since a portion with a large moving amount must be determined as a detection target, an increase in size of a device itself is unavoidable. Therefore, it had been difficult to achieve both a miniaturization of the device and the improvement of the tilt detection accuracy.